Should I change my compound?

[Jason B.]

I use a 1x30 leather belt with 6 micron DMT paste and it works very well, I've had to switch back to my HA chromium oxide though because I ran out of the DMT paste. Though the chromium oxide is finer the 6 micron paste produced a sharper and higher polish edge and when I go to my bull leather hand strops the results improve no matter what polish I have used on the power strop. Though I must agree most would not be able to tell the difference, but then again could they?

 

[stitchawl]

I use a 1x30 leather belt with 6 micron DMT paste and it works very well, I've had to switch back to my HA chromium oxide though because I ran out of the DMT paste. Though the chromium oxide is finer the 6 micron paste produced a sharper and higher polish edge and when I go to my bull leather hand strops the results improve no matter what polish I have used on the power strop. Though I must agree most would not be able to tell the difference, but then again could they?

Perhaps the real test should be on that which is usually cut. A sharp straight razor does a hell of a job on a beard but is about useless for cutting tomatoes! In fact, an old $2.95 "Ginsu" knife cuts a tomato better than most highly sharpened hunting knives. (I would not want to shave with it though. )

Cutting ability is not only dependent upon a fine edge. The blade also needs to have the correct geometry. Unfortunately, we get so caught up with testing these edges on toilet paper and hair that we forget we aren't using these knives to cut toilet paper and hair!! How does it work when you cut 1/2" hemp rope twenty times a day? How long does the edge last when you cut corrugated cardboard? How badly will that edge nick or chip when cutting a branch to make a 'Figure 4' deadfall?

Maybe those of us who have been sharpening a while are giving the wrong idea to some of the new sharpeners? Maybe we take for granted that we have to sharpen a fillet knife at 12 degrees and sharpen a Buck 110 used for cardboard at 22 degrees? Maybe we do this part without thinking about it, and only think about that final bevel, so that's what the new folks think is the end-all be-all of sharpening.

Sharpening is more than just the part that contacts the surface to be cut. It's making the blade perform properly for the tasks for which it will be used. Now I'll go back to sharpening my pocket comb.

Stitchawl

 

[Dog of War]

One of the biggest problems with using a written forum is that there is no 'body language' to help in the communication.

Amen to that! I think we're seeing a very graphic demonstration in this thread. Be nice if we could all sit down over a beer -- betcha you'd see very little disagreement, if any.

Actually I've thought a lot about this sort of thing lately, just in a slightly different context: that being, how can a ceramic rod sharpener like a Sharpmaker or Crocksticks, improve the edge of steels with high vanadium carbide content, when vanadium carbide is harder than the aluminum oxide ceramic of the rods? I'm no materials engineer or scientist, but my uneducated wager is that, in both cases, we see some improvement to our edges because both red rouge and aluminum oxide are harder than the actual steel matrix/substrate. The hard carbides aren't being affected at all, unless maybe a few fall or tear lose as the steel around them is removed.

You know... That makes perfect sense to me! There really isn't much carbide in hard steel. Just a few percent, if that much. Most of the metal is still steel/iron, etc. (I know diddly about metalurgy.) Metal is certainly being removed with ceramics, and can clearly be seen streaking the rods.

Here is another thought. (And I have no real reason to think it is so...) Many compounds oxidize very quickly. Oils, in fact, begin to oxidize the moment they are exposed to air, especially vegetable oils. I wonder if metals do this too, and the primary action that we see when using red rouge might be simply removal of this oxidation? Obviously, as Bil DeShiv says, red rouge will cut eventually (speeded up by a power buffing wheel to remove the 'eventually' part,) but could that bright finish be partly responsible to oxidation removal? Hmmmmm....

I'm sure the seemingly simple action of polishing metal surfaces with an abrasive is a lot more complex than we might think at first. Obviously that's the case when using an abrasive that's harder than the steel substrate but softer than the carbide aggregates, as compared to what's going on when using diamond abrasive.

Having watched steels rust literally before my eyes, you could be right about rouge. In fact, I'm wondering now if it could be that, when stropping on something like untreated leather or even denim, paper, etc., if there isn't some effect, albeit perhaps pretty minimal most of the time, from the oxide on the surface of the steel being transferred to the stropping medium, where it then starts to act as an abrasive?

It's interesting trying to square what we've seen and experienced first-hand with the science and facts we learn. It's because of everyone's different experiences, observations and understanding that these forums and discussions can be so informative, and at least for me, valuable.

Good thread, all. :thumbup:

 

[Dog of War]

OK ... from what I've found that looks somewhat credible, rouge (ferric oxide) has a hardness range from 5.5 - 6.5 Mohs. And 6.5 Mohs appears to be about the upper range of hardness for ordinary tool steel, e.g. a file.

I guess I'll let everyone who's interested draw their own conclusions:

http://en.wikipedia.org/wiki/Hematite

(see also: http://en.wikipedia.org/wiki/Iron_oxide)

http://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness

http://www.diamonds-are-forever.org.uk/mohs-hardness-scale.htm

http://www.bbc.co.uk/dna/h2g2/A2982576

http://www.efunda.com/units/hardness/convert_hardness.cfm?cat=Steel&HD=HM

http://www.reade.com/Particle_Briefings/mohs_hardness_abrasive_grit.html

 

[Bill DeShivs]

The sharpening medium does not have to be harder than the steel.

 

[bgentry]

A minute or two on a powered strop with red rouge... a minute or two on a hand strop with diamond compound.... I doubt the difference can be seen or felt by the average user.

How many of us have or use powered strops?

As I said earlier in the thread, I've used red rouge on a powered cloth wheel to put a final sharpening on knives. It made a huge difference. Back then I didn't know about strops and this cloth wheel was something I had never seen before. As I said, it worked. I can't really compare it to anything else because we didn't have strops or fine ceramic stones or anything. I just know if made chisels and knives far sharper than when we started.

Brian.

 

[stitchawl]

So far, the folks replying using red rouge all have been using it on powered devices. POWERED DEVICES. I think this, of all things, may be what makes it a viable sharpening addition. The compression of the time factor provided by the powered tools. Without it, red rouge might just be removing oxides. To refer back to my 'water polishing' analogy, the same can be said. Water polishes (or abrades) rock. It just takes enough time.

Does this mean that red rouge is NOT viable for hand stropping (as opposed to powered stropping?) Personally, I haven't found it so. (And I have tried it.) I use it often in jewelery making, both on powered buffing wheels and hand cloths. It does a great job on the silver guards and pommels of knives, as well as rings and pendants. But for stropping blades on a hand strop.... nah. Not for me. I'll finish an edge with CrO2 on MDF or leather, followed by gentle stropping on a bare good quality leather strop.

Stitchawl

 

[Bill DeShivs]

Crocus cloth is iron oxide. It will polish metals. It is also used on jewelers fine emory sticks.

 

[stitchawl]

Crocus cloth is iron oxide. It will polish metals. It is also used on jewelers fine emory sticks.

Emery is actually a combination of Iron Oxide and Corundum (aluminum oxide plus a bit of titanium and chromium ) which is MUCH harder than iron oxide alone. Aluminum Oxide (Al2O3 ) is used to cut and polish gem stones!! In fact, rubies and sapphires ARE aluminum oxide in crystal form.
I guess the hell it sure will polish metal! There isn't too much on this planet harder!

But to polish hard steel with just Fe203 (Iron Oxide) alone... That takes either a loooong time or a powered buffer!

Stitchawl

 

[huugh]

With all due respect, have you any credible sources you can cite for this?

You mean something like this?

As discussed above, it was initially thought that a clean strop would contain enough natural abrasive material to produce a marked improvement in the quality of the
edge. As a result, several initial experiments were done with clean leather strops,
including an experiment with alternate 3 cycles of 4 leather stropping plus a single 6000
grit sharpening. In all cases the clean leather stropping proved ineffective in comparison
with the dramatic improvement found with the chrome oxide loaded strop

 

[Jason B.]

Wow, someone actually took the time to read the Verhoeven paper.

 

[stitchawl]

You mean something like this?
In all cases the clean leather stropping proved ineffective in comparison
with the dramatic improvement found with the chrome oxide loaded strop

Sometimes reading comprehension suffers when one is trying so hard to make a point.
There was never any doubt that Cr02 cuts faster than a bare strop. No one claimed otherwise. For that matter, diamond compound cuts faster than CrO2! So what?

What was said was that there is absolutely no reason to put compound ON a bare strop. It's more abrasive than a bare strop. A bare strop is used AFTER stropping with a compound, not instead of. It gives a finer finish than compound. It's the next step up the grit ladder.

Think of it this way; would you sand a piece of wood using first 600 grit sandpaper then follow with 350 grit sand paper? Of course not. It doesn't get smoother that way. Would you put that sandpaper on a sanding block made of wood, or would you spend a lot of money and purchase a block of silver to use as your sanding block? Of course not! It would work, but why waste the money?

Chromium Oxide works very well. A bare strop works very well. (That explains why barbers have been using them for the last few centuries.) You just have to use them in the correct order. As I said before, putting compound on a quality leather is like bronzing a gold medal. Perhaps some people like bronze gold medals.
It's not saying that compounds don't work.
Verhoeven only says CrO2 cuts faster than bare leather. Of course it does. No surprise there.

Stitchawl

 

[Bill DeShivs]

We call them "emory sticks," but that doesn't mean one that has crocus cloth as the abrasive paper contains emory.
Iron oxide does not cut steel as fast as other abrasives, of course.

 

[huugh]

Sometimes reading comprehension suffers when one is trying so hard to make a point.
There was never any doubt that Cr02 cuts faster than a bare strop. No one claimed otherwise. For that matter, diamond compound cuts faster than CrO2! So what?

What was said was that there is absolutely no reason to put compound ON a bare strop. It's more abrasive than a bare strop. A bare strop is used AFTER stropping with a compound, not instead of. It gives a finer finish than compound. It's the next step up the grit ladder.

Think of it this way; would you sand a piece of wood using first 600 grit sandpaper then follow with 350 grit sand paper? Of course not. It doesn't get smoother that way. Would you put that sandpaper on a sanding block made of wood, or would you spend a lot of money and purchase a block of silver to use as your sanding block? Of course not! It would work, but why waste the money?

Chromium Oxide works very well. A bare strop works very well. (That explains why barbers have been using them for the last few centuries.) You just have to use them in the correct order. As I said before, putting compound on a quality leather is like bronzing a gold medal. Perhaps some people like bronze gold medals.
It's not saying that compounds don't work.
Verhoeven only says CrO2 cuts faster than bare leather. Of course it does. No surprise there.

Stitchawl

Oh my. Did you even bother to read that paper?
And you should differ between sharpening a knife, where you do not want any kind of wire edge and maintaining a razor, where in fact it is the very goal (and stropping on bare leather only helps to align it).

 

[stitchawl]

Oh my. Did you even bother to read that paper?

I read what you wrote and posted, and responded to it.
If you wanted a response to the whole paper you might have asked for that. I'd be happy to oblige.

And you should

I should? :jerkit:

stropping on bare leather only helps to align it.

Probably spending too much time reading...
You are aware, I'm sure, that his work is five years out of date... In materials engineering, five years is a looong time... Just think how many new steels have been introduced to the knife community in that time. Five years ago many people were still touting 440C. ATS34 was the being used by only the better knife makers. We've come a long way since then.

You might believe that stropping only aligns an edge. I believe that proper stropping polishes out the scratch marks left by coarser grits and gives me a much sharper edge. I know this from 50+ years of using a strop. Not from reading and quoting someone else's work. There is a difference. However, if you choose to believe otherwise, you are more than welcome to do so. We all have our own ways of dealing with edges. We can agree to disagree.

Stitchawl

 

[Dog of War]

Wow, someone actually took the time to read the Verhoeven paper.

LOL! I know I got bogged down ... uh, well, not too far in. But I did skim the rest of it, sort of.

Note, too, the rather noncommittal wording: "the clean leather stropping proved ineffective in comparison with the dramatic improvement found with the chrome oxide loaded strop." One might similarly observe that "the .5 micron paste proved ineffective in comparison with the dramatic improvement found with the DMT XX coarse hone when reprofiling the edge of a large kukri."

 

[Jason B.]

3 Stropping of the waterstone sharpened blades on clean leather strops had little effect
upon the geometry of the as-sharpened blades. The abrasive grooves on faces and the bur
size along the edge were not significantly modified. The burs on 600 grit pre-sharpened
blades were not effectively removed. Apparently, the natural abrasives in clean leather,
on either the hard or soft side of the leather, is not adequate to produce a significant
abrasion of the surface.
4 Stropping of the waterstone sharpened blades on a leather strop loaded with chrome
oxide compound produced a significant change in the edge geometry of the blades. The
abrasive grooves from the waterstone sharpening were smoothed out significantly. The
edge bur width was not reduced significantly below the 0.5 micron level of the
waterstone ground blades, but it was perhaps a bit more uniform along the edge.
However, the burs on 600 grit pre-sharpened blades were reduced significantly, to the
same level as on the pre-sharpened waterstone blades. The overall geometry of the
stropped edges compared favorably to the razor blade standards.

Stitchawl, I know you like using natural leather but science points to the fact that it does little if anything to improve the edge. If we all want to continue to bicker about what does what then why not look to science to prove us right or wrong?

 

[65535]

I think the be all end all in this argument, is once you hit stropping, you're nearing diminishing returns, you can only strop so much to produce a finer edge.

I use a Cr2O3 loaded strop to put a polished edge on my knives, then I hit it with a bare strop to put a final hone on the edge.

If you were only going to use 1 strop ever for an EDC or a user, go with a loaded strop it works faster.

 

[stitchawl]

Stitchawl, I know you like using natural leather but science points to the fact that it does little if anything to improve the edge. If we all want to continue to bicker about what does what then why not look to science to prove us right or wrong?

Science usually has to opposing camps for every issue. Just because someone is called a scientist doesn't make them accurate. In fact, what usually happens is that scientists always seem to run tests that prove their hypothesis rather than disprove it. It takes the folks on the other team to disprove it and only prove their own. Time and time again

Have you looked closely at the HandAmerican site? Some quotes;

"Honing Pads - Accessories
Over the years we've developed various honing surfaces for use with compounds or just by themselves.

Hard rolled horse butt - [SNIP] imparts a fabulous finish edge on all blades from the finest Japanese knives to the thinnest full hollow razors. No compound is required with this leather.


[SNIP] it's very similar to the handamerican red leather we produced years ago. When you strop using this type of hide it is very much like stropping on a super fine grit stone

There is more, but I'll stop here and ask a question;
If you go to a barber to get a shave, would you prefer he strops his razor before he shaves you or would you tell him not to bother?

Stitchawl

 

[Jason B.]

I see your point about the scientist thing, I guess I also was not taking into account the type of leather he may have been using. I have a horse butt barber strop that I have used bare with good success but its now covered with 0.5 micron diamond spray and dare I say it gets knives much sharper. I personally use HA scrubbed bull leather with diamond spray and it has worked so well I have given up on their standard cowhide leather. I would like to try some of that SNIP leather one day but because my steel selection is made up of mainly high carbide super steels using anything but diamond compound does not give me the results I have become accustom too.

Saying that bare strop leather will work fine is kinda a blanket statement, sure it will work but not on all steels and there are many different kinds of strop leather to chose from.

I want him to strop it but I would feel better if his strop had diamond compound on it